Magnetic material.



l.. T. .FREDERICK l.. IVICCULLOCH.

MAGNETIC MATERIAL. APPLICATION FILED lAN. 7, |914.

` 1,231,588. PatenteaJulys, 1917.

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LOUIS T. FREDERICK AND LEON I VICCULLOCH, OF WILKINSBURG, PENNSYLVANIA, ASSIGNORS TQ WESTINGHOUSE ELECTRIC AND MANUFACTURING'COMPANY, `A

CORPORATION OF PENNSYLVANIA.

" MAGNETIC MATERIAL.

CnLLocu, a. citizen of the United States, and

a resident of IVilkiushurg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Magnetic Material, of which the following is a specification.

Our invention relates to the manufacture of magnetic material, and it has particular reference to the manufacture of such material to he formed into wedges for use in the slots of dynamo-electric machines.

In induction motors and other dynamoelectric'l machines which comprise magnetizable co`re members having coil-containing slots, it is desirable that the coils be of the partiallyclosed type, since, vby the use. of

this type of coils, eddy currents are minimized and slot leakage decreased, with consequent lowering of the reactance ofthemachine and a proportional increase in its genera-l ellicieiicy. Furthermore, when the slotted core is the. rotor of the machine, the partial 4closure of the slots serves to hold the coils firmly against centrifugal or other displacement.

- On the other hand, the open type ofslot having parallel sides is preferable on account of certain mechanical considerations,

among which are simplicity of construction and the fact that the coils may be readily reached for removing or repairing them. It has therefore been found desirable to combine the advantages of both types of slots by providing slots of the open type and slip-A plying them with removable wedges of mag- 'netic material. These ,wedges have heretofore usually been composed of two strips of a magnetic substance,. such as iron or steel and a separating stripof non-magnetic substance, such as brass. v

It is the object of our invention to provide a cheap and efficient magnetic material from which unitary wedges may be made which will have the same eiect as the tripartite wedges heretofore used. i

Our inventioncomprehends our improved magnetic materialand the steps of the process by which it is produced. l In general, we proceed Specification o! Letters Patent.

Application ined Jauary 7,1914. serial No. 810,872.

by distributing y Patented July 3, 191 '7.

separate bodies of a magnetic substance throughout a mass of non-magnetic material which serves as a binder and carrier for the magnetic bodies. At suitable intervals, we provlde sections composed entirely of non-magnetic material so vas to enable 'wedges to be out, each offwhich will include one of these entirely non-magnetic portions to constitute the necessary magnetic gap in the wedge. IVe have found it convenient to prepare the mass in the form of a laminated fabric having strips, wire or finely divided particles of a magnetic substance, such as iron, disposed between the/laminations.

- 'lhe nature of our invention will be best understood by reference to the accompanylng drawings, in which Figure l is a fragmentary perspective view showing one manner in which th'e laminations may be stacked in the first stage of our process; Fig. 2 is a fragmentary perspective view showing another 'laminated arrangement built up in accoi-dance with ur process; Fig. 3 is a perspective view of a composite sheet formed by pressing the stack of material shown in F 2; Fig. 4 is a view similar to Fig. 3 showlig a composite sheet in which metallic ribbons are embedded; Fig. 5 is another View similar to Fig. 3 showing a composite sheet having a finely divided magnetic substance distrib- Fig. 9 is an elevational View showing a se- 'rlesof core slots, one of which is provided with one of our improved Wedges.

Referring now to Figs. 1 and 2 `of the drawing, wires 1 of a magnetic material are laid, woven or stretched'parallel to one another. This may be conveniently done by weaving a fabric in whiclrthe' warp is composed of fine wire and the weft of cotton or similar thread. Such a` fabric is shown in Fig. 1, in which the wires 1 are woven with threads 2. The wires or wire-fabric sheets are then sandwiched between sheets of paper or cloth 3 3 treated-with a phenolic condensation product or other adhesive insulatnated sheet of non-magnetic material having bodies of magnetic material distributed therethrough, dividing the sheet into parallel spaced strips, filling the spaces between the strips with non-magnetic material and pressing the sheet between layers or' librous material.

9. A process otl making magnetic material which comprises preparing a laminated sheet or' non-magnetie `material having bodies of magnetic material evenly distributed therethrough, dividing the sheets into evenly spaced parallel strips, lilling the spaces between the strips with a cement, hot-pressing the spaced strips between two sheets of fibrous material and dividing the sheet into strips by cuts parallel to and spaced from the cement-lilled spaces.

10. As a new article of manufacture, magnetic material comprising a laminated sheet of non-magnetic material having bodies of a magnetic substance distributed therethrough.

11. As a new article of manufacture,mag-

13. As a new article of manufacture, a magnetic material comprising a mass of non-magnetic material having a relatively large number et' parallel wires of a magnetic substance distributed therethrough, relatively narrow spaced sections of a cement disposed transversely to the wires and extending completely through the mass, and sheets of non-magnetic material inclosing the mass.

11A wedge for closing core slots ol dynamo-electric machines comprising a unitary strip having an intermediate longitudinal section et' non-magnetic n'iaterial and two longitudinal outer sections composed of transversely disposed wires ot a magnetic material compressed between laminations ot nonanagnetic material.

l5. A wedge for closing core slots oi dyi1amoelectric machines comprising a unitary strip having an intermediate longitudinal section ot' non-magnetic material and two longitudinal outer sect-ions composed ot laminated non-magnetic material having bodies of a magnetic substance' distributed therethrough.

In testimony whereof, we have hereunto subscribed our names this 31st day ot' Dec., 1913.

LOUIS T. FREDERICK. LEON MCCULLOCH. Vitnesses PmLLirs THOMAS, B. B. Hines. 

